Shock absorbing device



Aug. 22, 1939.

R. L. KERR SHOCK ABSORBING DEVICE Filed Jan. 11, 1939 F/GZ.

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Patented Aug. 22., 1'939 PATEN orne 2,170,051 snoek Asonme DEVICE Ralph L. Kerr, Oklahoma City,

t- J. Eldon Peek, -0

one- Okla.

Application January ll, 1939, Serial This invention relates to a shock absorbing device designed for the purpose of cushioning the shocks incident to the handling of rods or tubing within a bore hole.

In drilling a bore hole, it is repeatedly neces'- sary to lower intoand withdraw from the hole strings of rods or tubing which support bits or other devices. The withdrawals and'replacements of such strings are necessary, for example, to change bits as well as V'for other less frequent purposes. In the customary apparatus for the handling ofv these strings of rods or tubing, there are used elevators, slips, and the like which in the lowering of the strings which they support involve the production of impacts of enormous amounts when the strings are brought to rest, since these strings may be .several thousand feet in length and of corresponding weight.

It is the object of the present invention to provide means for minimizing damage to the various parts involved during the handling of tool strings of the types present device is in the nature of a cushioned spider preferably of hydraulic type to gradually absorb the shocks attendant upon stopping of the lowering so as to bring lthe strings to rest more gradually. The invention is applicable to various specic forms of handling devices, for example, to the elevators generally usedfor the handling of rods and slips for the handling of tubing.

The broad object just indicated,

as well as subsidiary objects relating to details, will be ap- .'parent from the following description, read in conjunction with the accompanying drawing, in which:

Figure 1 is a vertical sectional view of the improved type of 4shock 4absorbing spider in a form particularly adapted for cooperation` with an elevator-for' the handling of rods;

Figure 2 is a fragmentary section talen on the plane indie/ated at 2-2 i'n Figure 1, and particularly showing the ilow restricting arrangement used forf shock absorption; and

Figure 3 is a diagrammatic view partially in section showing the modication involved in adapting the device of Figure 1 foruse on a rotary table in conjunction with slips for handling tubing.

50 Referring rst illustrated therein to Figures 1 and 2, there is a base member 2 siu'rounding the xed element 4 in order to strengthen the same and, under some circumstances, provide a base therefor. The xed member 4 is inter- 55 nally threaded to be adapted for location upon indicated. Specically, the

Okla., assigner oi o City,

(ci. g55-i) the upper end of one or more sizes of casngs, indicated at 6, the casing in this modication serving for the support of the spider at the mouth of the hole.

The member d is internally bored as indi- 5 .cated at l for the passage of the rods which are to extend linto the hole, one section of a rod string Abeing indicated at '42.

The member 4 is provided with a piston 8, provided with an opening including an upwardly l0 opening check valve' II, which piston is iixed in this modication and which is surrounded by a. cylinder I0 formed in`a moving member 9. The wall of this cylinder Il) is bored in a plurality of locations about its circumference as indicated l5 at I2, the bores intersecting the cylinder walls. Within each of these' bores there is located a cylindrical filler indicated at I4 provided with a longitudinal hole I6 and aslit I8 running lengthwise of it `and communicating with the interior 20 of the cylinder. 'Ihese llers I4 may be held in position by the member which provides a lower head for the cylinder lI0. Packing 22 is provided in this head to form a liquid tight joint with the outer cylindrical surface of the mem- 25 ber d.

The movable member 9 may be cast with an annular .socket 24 adapted` to receive a strong spring 26 arranged to bear upon the upper face of the piston and thus normally urge the movable member upwardly with respect to the lixed member 4. A cylindrical wall 28 is provided on the inside oi the member 9 for the reception of the upper extension 30 of the xed member 4.

Packing 32 is located between these members and 35 there are preferably provided liquid passages indicated at 34 for the purpose of exerting pressure on the packing to maintain a liquid tight contact with the wall 28.

`At its upper end the movable member 9 is 40 provided with an abutment face 36 through which there is a bore 38 corresponding in diameter to the bore 6 of the fixed member 4. The face 36 is designed to provide a rest for an elevator u sed for the handling of the rods 42.

In the operation of this device the cylinder is lilled with a suitable liquid such as oil the visj cosity of which may be chosen relative to the `slits I8 to secure the desired amount of cushioning. Normally, the movablek member within A5 which the cylinder I0 is formed will occupy an upper position by reason of the action of the spring 2G. AWhen the string of rods extending through the device are lowered and the elevator 68 contacts with the face, the impact will be 55 absorbed by the passage of oil from the cylinder space above the piston 8 to the cylinder space below the piston through the restricted passage formed by the slits I8 and the openings I6 through the iillers I4. The movable member can move under the restraint imposed by the oil or other liquid until'it engages the member 2, whereupon it will be definitely arrested. However, by the time such contact takes place, the major portion of, the inertia of the string will have been absorbed in the liquid. Upon release of the elevator 40 the device is restored to its original position by the action of the spring 26, the valve Il opening to permit a rapid return `It will be obvious that the apparatus may take various forms. For example, the piston and cylinder may be interchanged so that the former is on the movable member and the latter on the fixed member, or a plurality of pistons and cylinders may be provided. Desirably any such modiiication should provide not only for the cushioning of the shock, but for the return of the device to normal condition for the reception of a subsequent shock. Instead of using hydraulic cushioning means, it will, of course, be obvious that spring means alone may be used; but these are not as satisfactory since the resistance offered by a hydraulic shock absorbing device is dependent upon the imposed velocity of movement and very definitely slows down that movement, particularly under heavy shocks.

In order to provide an illustration of the adaptation of this device to a somewhat different handling of strings of tubing within well bores, there is illustrated in Figure 3 at 44 a rotary table on which may be secured the member 46 forming the base of the fixed member of the shock absorbing device indicated at 48, which iixed member corresponds to 4 of the previous modification. The movable member is indicated at 50. Though not shown in Figure 3, it will be understood that the members 48 and 50 are' provided with a piston and cylinder respectively and associated with a spring such as 26 and the other devices of the previous modication. The movable member in this form of the device is provided with an upper portion 52 adapted for the reception of slips 54 adapted to engage the tubing indicated at 56; It will be obvious that the shock absorbing action of this modification is the same gstizlt of the modication previously described in What I claim and desire Patent is:

1. Means for absorbing shocks of devices being moved within a bore hole comprising a xed member provided`wlth a central passage for said devices and adapted to be secured above the end of a. hole, a member guided by and movable relative to said xed member, said movable member being provided with means engageable to arrest said devices when they are lowered, and shock absorbing means between said members.

2. Means for absorbing shocks of devices being moved within a bore hole comprising a iixed member provided with a central passage for said devices and adapted to be secured above the end of a hole, a member guided by and movable relative to said xed member, said movable member being provided with means engageable to arrest said devices when they are lowered, and hyto protect by Letters draulic shock absorbing means between said members.

3. Means for absorbing shocks of devices being moved within a bore hole comprising a xed member provided with a central passage for said devices and adapted to be secured above the end of a hole. a member guided by and movable relative to said xed member, said movable member being provided with means engageable to arrest 'said devices when they are lowered, shock absrbing means between said members, and means for restoring the movable member to its original position after a load is removed therefrom.

4. Means for absorbing shocks of devices being moved within a bore hole comprising a xed member provided with a central passage for said devices and adapted to be secured above the end of a hole, a member guided by and movable relative to said fixed member, said movable member being provided with means engageable to arrest said devices when they are lowered, hydraulic shock absorbing means between said members, and means for restoring the movable member to its original position after a lo'ad is removed therefrom.

5. Means for absorbing shocks of devices being moved within a bore hole comprisingv a fixed member provided with a central passage for said devices and adapted to be secured above the end of a hole, a member guided by and movable relative to said fixed member, said movable member being provided with means engageable to arrest said devices when they are lowered, a hydraulic shock absorbing means between said members. said hydraulic shock absorbing means comprising 'piston and cylinder elements one' connected to said iixed member and the other connected to said movable member, and means providing restricted bypass of liquid about the piston element during relative movement of said elements.

6. Means for absorbing shocks of devices being moved within a bore hole comprising a fixed i member provided with a central passage for said ber being provided with means engageable to arrest said devices when they are lowered, a hydraulic shock absorbing means between said members, said hydraulic shock absorbing means lcomprising piston and cylinder elements one connected to said xed member and the other connected to said movable member, and means providing restricted bypass of liquid about the piston element during relative movement of said elements, and means for restoring the movable member to its original position after a load is removed therefrom.

7. Means for absorbing shocks of devices being moved within a bore hole comprising a fixed member provided with a central passage for said devices and adapted to be secured above the end of a hole, a member guided by and movable relative to said iixed member, said movable member being provided with means engageable to arrest said. devices when they are lowered, a hydraulic 'shock absorbing means between said members, said hydraulic shock absorbing means comprising piston and cylinder elements one of which is connected to said xed member and the other of which is connected to said movable member, said cylinder element providing an annular liquid space about said central passage of the fixed member, and means providing a restricted passage of liquid past said piston element during relative movements of the cylinder and piston elements.

8. Means for absorbing shocks of devices being moved within a bore hole comprising a xed member provided with a central passage for said devices and adapted to be secured above the end of a hole, a member guided by and movable rela'- tive to said iixed member, said movable member being provided with means engageable to arrest said devices when they are lowered, a hydraulic shock absorbing means between said members, said hydraulic shock absorbing means comprising piston and cylinder elements one of 10 which is connected to said iixed member and the other of which is connected to said movable member, said cylinder element providing an annular liquid space about said central passage of the xed member, and means providing a restricted passage of liquid past said piston ele-- ment during relative movements of th'e cylinder and piston elements, and means for restoring the movable member to its original position after a load is rem'oved therefrom. l

Y RALPH L. KERR. 

